What are the dangers of smoking while pregnant?

The dangers of smoking are well documented and more scientific evidence is being presented each year, increasing our understanding of the detrimental impact smoking can have. Smoking cigarettes is already known to increase the risk of cardiovascular disease, cancers (over 90% of all diagnosed lung cancer cases are caused by smoking) and chronic obstructive pulmonary disease (COPD). The chemicals contained in cigarettes can also raise blood pressure, decrease fertility and contribute to erectile dysfunction in men.

For expectant mothers the dangers of smoking while pregnant are just as harmful, and they can also negatively affect the health and development of their unborn baby. Despite these dangers, some women continue to smoke during pregnancy.

How does smoking during pregnancy affect a baby?

When in the womb, unborn babies rely on their mother for all of their nourishment and oxygen, which is transferred through the placenta and umbilical cord. However, when people smoke, part of the oxygen in their blood is replaced by carbon monoxide. When this occurs in pregnant women, the amount of oxygen in their blood – and in the baby’s – is reduced and causes the foetal heart rate to increase as it struggles to cope with the decrease in oxygen levels.

There are over 4,000 chemicals in cigarettes, many of which which can affect the placenta and the baby’s development. Babies whose mothers smoked during pregnancy are more likely to be born prematurely, weigh on average 200g less than those born to non-smokers and have poorer lung function. They are also more likely to be asthmatic, fall ill and have smaller organs. (Source: NetDoctor).

These developmental issues from smoking during pregnancy have also been further highlighted in a recent French study reported by the BBC. The researchers from Nantes University Hospital took regular photographs of embryos fertilised for IVF, beginning at initial fertilisation, until it was ready to implant. They found that at all stages of development, the embryos from smokers were behind their non-smoker counterparts by a few hours.

All together it took embryos of non-smokers about 49 hours to reach the five-cell stage, whereas the children of smokers took 50 hours. Eight-cell stage took 58 hours for non-smokers’ babies and 62 hours for a smoker’s foetus. These results were consistent across 139 embryos from smokers, with a total of 868 in total.

This is the first time embryos have been observed during development for IVF using an embryoscope. The device is able to capture images in real time without disrupting the growth. Although the extent of impact smoking can have on the embryo was not discussed in this study, the researchers still argued that quitting smoking remains the best option for falling pregnant, as well as protecting the baby’s health and improving development.